Retinitis pigmentosa (RP) is the most common inherited form of retinal degeneration [1]. RP can be caused by mutations in an assortment of different genes, many of them photoreceptor-specific [1]. Therefore, elucidation of the photoreceptor gene regulatory network is fundamental to discerning the mechanism behind photoreceptor development and degeneration. Phenotypes resulting from the retinal deletion of Dicer, a critical enzyme required for small RNA processing, have established microRNAs (miRNAs), as key factors in retinal development and degeneration [2, 3]. MiRNAs modify gene expression at the post-transcriptional level [4]. Nonetheless, little is known about their role within photoreceptor development and degeneration. The goal of this proposal is to study the function of miRNAs in photoreceptor development, differentiation and degeneration. To achieve this goal, two aims have been designed to elucidate the transcriptional network regulating miRNA expression in photoreceptors and to understand the function of miR-124, the most highly expressed miRNA in retina. These aims will be accomplished using next generation sequencing, bioinformatic analysis, in situ hybridization, RT-PCR, immunohistochemistry, cloning techniques and tissue electroporation. PUBLIC HEALTH RELEVANCE: Understanding the cellular mechanism behind retinal neurodegeneration is essential for treating diseases that result in blindness, such as retinitis pigmentosa. MicroRNAs act post-transcriptionally to modify gene expression in cells. Elucidating the function of microRNAs in the retina may yield in the development of novel methods for therapy and treatment of retinitis pigmentosa.